Vibrio parahaemolyticus Infection Induces Modulation of IL-8 Secretion Through Dual Pathway via VP1680 in Caco-2 Cells

Shimohata, Takaaki; Nakano, Masayuki; Lian, Xin; Shigeyama, Tomomi; Iba, Hitomi; Hamamoto, Akiko; Yoshida, Masaki; Harada, Nagakatsu; Yamamoto, Hironori; Yamato, Masayuki; Mawatari, Kazuaki; Takahashi, Toshiaki; Nakaya, Yutaka; Takahashi, Akira

doi:10.1093/infdis/jiq070

Cited by 42 publications

(33 citation statements)

References 38 publications

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“…We show that VopQ directly forms small pores within minutes, allowing the release of small molecules from acidic compartments, causing a collapse of ion homeostasis inside eukaryotic cells. Previously, the activity of VopQ was implicated in modulating MAPK signaling and inducing IL-8 secretion during V. parahaemolyticus infection (18,19); researchers have shown that pore-forming toxins can directly regulate these same pathways (20). Therefore, we hypothesize that VopQ could induce IL-8 secretion by forming pores and rapidly disturbing cytosolic ion concentrations.…”

Section: Discussionmentioning

confidence: 90%

Vibrio effector protein, VopQ, forms a lysosomal gated channel that disrupts host ion homeostasis and autophagic flux

Sreelatha¹,

Bennett²,

Zheng

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Defects in normal autophagic pathways are implicated in numerous human diseases-such as neurodegenerative diseases, cancer, and cardiomyopathy-highlighting the importance of autophagy and its proper regulation. Herein we show that Vibrio parahaemolyticus uses the type III effector VopQ (Vibrio outer protein Q) to alter autophagic flux by manipulating the partitioning of small molecules and ions in the lysosome. This effector binds to the conserved V o domain of the vacuolar-type H + -ATPase and causes deacidification of the lysosomes within minutes of entering the host cell. VopQ forms a gated channel ∼18 Å in diameter that facilitates outward flux of ions across lipid bilayers. The electrostatic interactions of this type 3 secretion system effector with target membranes dictate its preference for host vacuolar-type H + -ATPase-containing membranes, indicating that its pore-forming activity is specific and not promiscuous. As seen with other effectors, VopQ is exploiting a eukaryotic mechanism, in this case manipulating lysosomal homeostasis and autophagic flux through transmembrane permeation.utophagy is a cellular process by which cells degrade and recycle cytoplasmic contents by encapsulating them within a distinctive double bilayer membrane vesicle for delivery to the degradative lysosome (1). Disruption of normal autophagic pathways is implicated in numerous human diseases, stressing the importance of autophagy and its proper regulation (2). Vibrio parahaemolyticus, a Gram-negative marine bacterium and a major cause of gastroenteritis due to the consumption of contaminated raw or undercooked seafood, induces autophagy during infection (3). V. parahaemolyticus harbors two type 3 secretion systems (T3SSs), molecular syringes that enable the translocation of bacterial proteins, known as effectors, into the eukaryotic host (3). The first T3SS (T3SS1) orchestrates a temporally regulated cell death mediated by the induction of autophagy, followed by cell rounding and resulting in lysis of the host cell (4). T3SS1 effector VopQ, also known as VepA (vp1680), is both necessary and sufficient for the rapid induction of autophagy, even in the presence of known chemical inhibitors of autophagy (5).VopQ is a 53-kDa protein with no apparent homology to any proteins outside of the Vibrio species. Vibrio homologs of VopQ have no known function or conserved structural domain. Previous work from our laboratory has shown that VopQ is a cytotoxic effector that accelerates host cell death and is essential in protecting V. parahaemolyticus from phagocytic uptake during infection (5). Based on microbial genetic studies, VopQ was shown to be necessary for the formation of an extensive network of autophagic vesicles in host cells within an hour of V. parahaemolyticus infection (5). Strikingly, recombinant VopQ alone is sufficient to induce this massive accumulation of autophagic vesicles, observed within minutes of microinjection of recombinant VopQ (picomolar concentrations) into eukaryotic cells (5). A recent report shows that Vo...

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Section: Discussionmentioning

confidence: 90%

Vibrio effector protein, VopQ, forms a lysosomal gated channel that disrupts host ion homeostasis and autophagic flux

Sreelatha¹,

Bennett²,

Zheng

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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“…Under such conditions, it has been previously demonstrated that wild-type cells do not express T3SS-1 genes (86). We first examined VP1680, which encodes the effector protein VopQ that is secreted via T3SS-1 and plays an important role in cytotoxicity as well as in the host immune response (8,44,60,73). We found an approximately 3-fold increase in VP1680 expression in the ⌬toxRS background compared to that in wild-type cells (P Ͻ 0.05) (Fig.…”

Section: Resultsmentioning

confidence: 96%

The Vibrio parahaemolyticus ToxRS Regulator Is Required for Stress Tolerance and Colonization in a Novel Orogastric Streptomycin-Induced Adult Murine Model

et al. 2012

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ABSTRACTVibrio parahaemolyticus, a marine bacterium, is the causative agent of gastroenteritis associated with the consumption of seafood. It contains a homologue of thetoxRSoperon that inV. choleraeis the key regulator of virulence gene expression. We examined a nonpolar mutation intoxRSto determine the role of these genes inV. parahaemolyticusRIMD2210633, an O3:K6 isolate, and showed that compared to the wild type, ΔtoxRSwas significantly more sensitive to acid, bile salts, and sodium dodecyl sulfate stresses. We demonstrated that ToxRS is a positive regulator ofompUexpression, and that the complementation of ΔtoxRSwithompUrestores stress tolerance. Furthermore, we showed that ToxRS also regulates type III secretion system genes in chromosome I via the regulation of theleuOhomologue VP0350. We examined the effect of ΔtoxRS in vivousing a new orogastric adult murine model of colonization. We demonstrated that streptomycin-treated adult C57BL/6 mice experienced prolonged intestinal colonization along the entire intestinal tract by the streptomycin-resistantV. parahaemolyticus. In contrast, no colonization occurred in non-streptomycin-treated mice. A competition assay between the ΔtoxRSand wild-typeV. parahaemolyticusstrains marked with the β-galactosidase genelacZdemonstrated that the ΔtoxRSstrain was defective in colonization compared to the wild-type strain. This defect was rescued by ectopically expressingompU. Thus, the defect in stress tolerance and colonization in ΔtoxRSis solely due to OmpU. To our knowledge, the orogastric adult murine model reported here is the first showing sustained intestinal colonization byV. parahaemolyticus.

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“…Most of the cytotoxicity produced by a V. parahaemolyticus infection can be attributed to the activity of the T3SS1 effector vopQ (12)(13)(14). Therefore, we examined the possibility that HU regulates T3SS1-related genes.…”

Section: Resultsmentioning

confidence: 99%

“…In particular, secretion of VopQ in host cells is both necessary and sufficient to induce an inflammatory response and cell death (12)(13)(14). The number of bacteria might also affect the cytotoxicity of the ⌬HUs strain, because V. parahaemolyticus could be grown during infection.…”

Section: Discussionmentioning

confidence: 99%

“…T3SS1 is responsible for cytotoxicity, whereas T3SS2 is related to enterotoxicity in mammalian cells (9)(10)(11). Cytotoxicity following V. parahaemolyticus infection is due primarily to the activity of the T3SS1 effector encoded by vp1680 (also known as vepA and vopQ), which is both necessary and sufficient for induction of an inflammatory response and cell death (12)(13)(14). Transcription of the T3SS1 genes of V. parahaemolyticus is controlled by a dual regulatory system consisting of the exsACDE regulatory cascade and nucleoid-associated protein (NAP) H-NS (15).…”

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confidence: 99%

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DNA-Binding Protein HU Coordinates Pathogenicity in Vibrio parahaemolyticus

et al. 2015

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HU is one of the most abundant nucleoid-associated proteins in bacterial cells and regulates the expression of many genes involved in growth, motility, metabolism, and virulence. It is known that Vibrio parahaemolyticus pathogenicity is related to its characteristic rapid growth and that type III secretion system 1 (T3SS1) contributes to its cytotoxicity. However, it is not known if HU plays a role in the pathogenicity of V. parahaemolyticus. In the present study, we investigated the effect of HU proteins HU-2 (HU␣) (V. parahaemolyticus 2911 [vp2911]) and HU␤ (vp0920) on the pathogenicity of V. parahaemolyticus. We found that a deletion of both HU subunits (yielding the ⌬HUs [⌬vp0920 ⌬vp2911] strain), but not single deletions, led to a reduction of the growth rate. In addition, expression levels of T3SS1-related genes, including exsA (positive regulator), exsD (negative regulator), vp1680 (cytotoxic effector), and vp1671 (T3SS1 apparatus), were reduced in the ⌬HUs strain compared to the wild type (WT). As a result, cytotoxicity to HeLa cells was decreased in the ⌬HUs strain. The additional deletion of exsD in the ⌬HUs strain restored T3SS1-related gene expression levels and cytotoxicity but not the growth rate. These results suggest that the HU protein regulates the levels of T3SS1 gene expression and cytotoxicity in a growth rate-independent manner. IMPORTANCENucleoid-binding protein HU regulates cellular behaviors, including nucleoid structuring, general recombination, transposition, growth, replication, motility, metabolism, and virulence. It is thought that both the number of bacteria and the number of virulence factors may affect the pathogenicity of bacteria. In the present study, we investigated which factor(s) has a dominant role during infection in one of the most rapidly growing bacterial species, Vibrio parahaemolyticus. We found that V. parahaemolyticus cytotoxicity is regulated, in a growth rate-independent manner, by the HU proteins through regulation of a number of virulence factors, including T3SS1 gene expression. Vibrio parahaemolyticus is a Gram-negative halophilic bacterium that causes seafood-associated gastroenteritis in several countries (1-3). This organism is one of the most rapidly growing bacterial species (4, 5), with a minimal doubling time in culture of less than 10 min. The rate of growth is thought to affect the pathogenicity of V. parahaemolyticus.V. parahaemolyticus virulence factors include thermostable direct hemolysin (TDH); TDH-related hemolysin (TRH); and two separate type III secretion systems (T3SSs), T3SS1 and T3SS2 (1, 6). T3SSs are protein export systems that secrete and translocate effector proteins into the cytoplasm of host cells. Translocated effectors modify host cell function and allow pathogens to promote infection and cause disease (7,8). T3SS1 is responsible for cytotoxicity, whereas T3SS2 is related to enterotoxicity in mammalian cells (9-11). Cytotoxicity following V. parahaemolyticus infection is due primarily to the activity of the T3SS1 effector e...

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Vibrio parahaemolyticus Infection Induces Modulation of IL-8 Secretion Through Dual Pathway via VP1680 in Caco-2 Cells

Abstract: We showed that V. parahaemolyticus infection of Caco-2 cells results in the secretion of IL-8, and that VP1680 plays a pivotal role in manipulating host cell signaling and is responsible for triggering IL-8 secretion.

Cited by 42 publications

References 38 publications

Vibrio effector protein, VopQ, forms a lysosomal gated channel that disrupts host ion homeostasis and autophagic flux

Vibrio effector protein, VopQ, forms a lysosomal gated channel that disrupts host ion homeostasis and autophagic flux

The Vibrio parahaemolyticus ToxRS Regulator Is Required for Stress Tolerance and Colonization in a Novel Orogastric Streptomycin-Induced Adult Murine Model

DNA-Binding Protein HU Coordinates Pathogenicity in Vibrio parahaemolyticus

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